NTI INSTALLATION MANUALS

Part 11 - Start-Up

Operation 4 - Checking the CO2 at Minimum Gas Flow (Low Fan Speed) With the Test Function active, press the button to operate the boiler at minimum DHW power. The and icons will display.

Wait 1 minute for the boiler to stabilize before carrying out the combustion analyses. If the CO2 (%) reading at min gas ow is greater than the CO2 (%) reading at max

ow, or if it is less than the reading at max ow by more than 0.3%, adjust the gas valve following the instructions below. Otherwise move directly to Operation 5.

Adjusting the Gas Valve at Minimum Gas Flow Remove cap and adjust screw 2 by turning counter-clockwise to reduce the CO2 level; clockwise to increase the CO2 level. Wait 1 minute after each adjustment for the CO2 value to stabilize. WARNING! Minimum Gas Flow Adjustment is very sensitive.

2

If the value measured corresponds to the value given in Table 33 adjustment is complete. Otherwise continue the setting procedure.

Figure 77 - Min CO2 Adjustment

Attention!! If the value of the CO2 at minimum power has been changed, it is necessary repeat the adjusting at maximum gas flow. Operation 5 - Ending Adjustment 1. Exit Test Mode by pressing RESET. 2. Turn down the thermostat and / or stop the DHW draw-o . For Only Heating Boiler applications reset all thermostatic valves. 3. Check for and repair any leaks of gas. 4. Reinstall the front cover. 5. Reinstall the combustion test port - see Figure 75.

79